The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Float operated pneumatic pumps have proven to be highly efficient and economical devices for use in groundwater remediation applications. The assignee of the present disclosure has been a leader in the manufacture of such pumps, and is the owner of the following U.S. patents, all of which are hereby incorporated by reference into the present disclosure: U.S. Pat. No. 6,039,546 to Edwards et al.; U.S. Pat. No. 5,358,037 to Edwards et al.; U.S. Pat. No. 5,358,038 to Edwards et al.; and U.S. Pat. No. 5,495,890.
Because float operated pneumatics pumps are often required to pump sludge-like fluids, there is a need for more frequent cleaning. This need for more frequent cleaning arises in part because of the relatively tight clearances within a typical float operated pneumatic pump. For example, the pump illustrated in U.S. Pat. No. 6,039,546 referenced above, is a four inch diameter pump. By that it is meant that the outer casing of the pump has a four inch diameter. The float inside the casing is about three inch in diameter. As such, the clearances are relatively tight. Therefore, while the four inch casing enables the pump to be used in smaller diameter well bores, the tight internal clearances will naturally give rise to a need for more frequent cleaning. This should not be viewed as a defect in any way; rather, there is simply a tradeoff between a highly compact pump construction that enables use in smaller diameter wells, and the cleaning service interval for the pump.
The cleaning of any float operated pneumatic pump can represent a time intensive endeavor. Depending on how dirty the pump is inside, it may be necessary for extensive disassembly of the pump which is not easy to do in the field, and thus may require taking the pump back to a service facility for a thorough cleaning. Accordingly, any pump construction which reduces the need for cleaning, as well as reduces the risk of fouling of the pump from contaminants, would be welcomed in the industry.
Another limitation with present day pneumatic pumps is the number of independent component parts that must be carried for a manufacturer to construct pumps of different diameters. For example, at the present time there is no easy way to alter a 4.0 inch diameter pump to make it into a 4.5 inch diameter pump. Instead, the user is typically forced to purchase an entirely new pump. And pump manufacturers often are required to carry separate inventories of parts needed to construct two otherwise very similar pumps but which have different diameters. In some applications it would be a significant advantage to be able to easily modify a pump to increase its dimensions, and particularly its diameter. Simply increasing the overall diameter of a pump can significantly reduce the chance of sticking of the float mechanism caused by contaminants such as solid and semi-solids which can coat the surfaces of the float and/or the internal wall of the casing and/or the rod on which the float travels. Providing a greater degree of clearance between the float and the float rod, and between the exterior surface of the float and the interior surface of the pump casing, can dramatically reduce the chance that the interior of the pump will become contaminated to the point of causing the float to stick. If the diameter of the pump could be easily modified by the manufacturer, or possibly even by the end user, to alter the diameter of the pump, then the manufacturer (and possibly even the user) would have the ability to tailor one pump for a greater variety of uses with minimal additional cost and minimal additional component parts. Potentially, the end user might even be able to buy one pump having a first diameter, and be able to reconfigure it as a pump having a second diameter, with only a few additional component parts, and without the need for buying an entirely complete second pump.